Peripheral nerves are nerves in the body other than the nerves of the brain or spinal cord. Peripheral nerve injury may result in the development of chronic intractable pain. Some patients prove unresponsive to conservative pain management techniques. Peripheral Nerve Stimulation (PNS) has developed as a successful therapy for pain management when the pain is known to result from a specific nerve. PNS is based in part on the Melzack-Wall gate control theory of pain. Sweet and Wespic first used electrical stimulation of peripheral nerves in the 1960s to mask the sensation of pain with a tingling sensation (paresthesia) caused by the electrical stimulation. Subsequent refinements in the technology, surgical technique and patient selection have led to improved long term results.
Efforts have been made to treat psychiatric disorders with peripheral/cranial nerve stimulation. Recently, partial benefits with vagus nerve stimulation in patients with depression have been described in U.S. Pat. No. 5,299,569. Another example of electrical stimulation to treat depression is described in U.S. Pat. No. 5,470,846, which discloses the use of transcranial pulsed magnetic fields to treat depression. Yet further, U.S. Pat. No. 5,263,480 describes that stimulation of the vagus nerve may control depression and compulsive eating disorders and U.S. Pat. No. 5,540,734 teaches stimulation of the trigeminal or glossopharyngeal nerves for psychiatric illness, such as depression.
Another example of peripheral nerve stimulations include, for example, stimulating the C2 dermatome area to treat occipital neuralgia, which may be defined generally as an intractable headache originating in the back of the head in the vicinity of the C2 dermatome area (U.S. Pat. No. 6,505,075). This method of delivering electrical stimulation energy to the C2 dermatome area to treat occipital neuralgia involves positioning stimulation electrodes of an implantable electrical stimulation lead with at least one electrode in the fascia superior to in a subcutaneous region proximate the C2 dermatome area.
Yet further, the use of electrical stimulation for treating neurological diseases, including such disorders as movement disorders including Parkinson's disease, essential tremor, dystonia, and chronic pain, have also been widely discussed in the literature. It has been recognized that electrical stimulation holds significant advantages over lesioning since lesioning destroys the nervous system tissue. In many instances, the preferred effect is to modulate neuronal activity. Electrical stimulation permits such modulation of the target neural structures and, equally importantly, does not require the destruction of nervous tissue. Such electrical stimulation procedures include electroconvulsive therapy (ECT), repetitive transcranial (rTMS) magnetic stimulation and vagal nerve stimulation (VNS).
Traditional treatment options, for some forms of intractable pain (occipital pain, traumatic brain injury) that have proven to be resistant to medications, usually involve chemical, thermal or surgical ablation procedures following diagnostic local anesthetic blockade. Surgical approaches include neurolysis or nerve sectioning of either the C2 dermatome area in the occipital scalp or at the upper cervical dorsal root exit zone (extradural). Forammal decompression of C2 roots as well as C2 ganglionectomy have also been effective in reported cases. The present invention is the first to describe electrical stimulation to treat such conditions that are resistant to medications.